Retaining keeper assembly for a hoisting device

ABSTRACT

A retaining keeper assembly for a hoisting device. A shank has a plurality of circumferential grooves perpendicular to an axis of the shank. A thrust bearing surrounds the shank and is supported by the hoisting device. A split retaining collar having a plurality of interior circular protrusions mates with the circumferential grooves in the shank to prevent axial movement of the shank. A cylindrical retaining keeper ring having an open top and an open bottom encloses the assembled retaining collar, the keeper ring having an inner diameter slightly larger than an outer diameter of the retaining collar. A pair of retaining rings surround the split retaining collar above and below the keeper ring to trap the keeper ring in place.

CROSS REFERENCE TO PENDING APPLICATIONS

This is a continuation-in-part patent application of U.S. patentapplication Ser. No. 10/634,255 filed Aug. 5, 2003 now U.S. Pat. No.7,000,905 entitled “Retaining Keeper Assembly for a Hoisting Device”.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a retaining keeper assembly for ahoisting device. In particular, the present invention relates to aretaining keeper assembly for a pulley block that will accommodaterotating swivel action and be sealed from the elements while alsopermitting easy disassembly and reassembly.

2. Prior Art

In various types of industrial hoisting devices, it is necessary anddesirable to swivel or rotate a load receiving member such as a hook,shackle or the like, with a hoisting portion, such as a pulley block.Examples of prior assemblies in hoisting devices are shown in Assignee's(The Crosby Group, Inc.) U.S. Pat. No. 4,669,907 entitled “IndustrialSwivel” and U.S. Pat. No. 4,475,755 entitled “Apparatus And Method ForAssembly-Disassembly of A Spring Loaded Hook”. The assembly of thedevice may include seals, gaskets and packings. Various parts of theassembly are subject to wear over time and must be replaced. The variousparts of the assembly should also be inspected from time to time inorder to observe wear and to assure that the parts are in working order.For example, API (American Petroleum Institute) Recommended Practice 8Brequires the periodic inspection at specific times of hoisting devicesincluding disassembly to inspect specific components.

Accordingly, it is an object and purpose of the present invention toprovide a retaining keeper assembly for a hoisting device wherein thecomponents may be easily disassembled and accessed for inspection andreplacement.

In the case of certain hoisting devices which are used in extremeenvironments, such as oilfield equipment, the equipment is subjected todust, dirt, corrosive environments, and extreme hot and cold conditions,and the swivel mechanism should be protected against all of theseconditions and the elements.

Accordingly, it is an object and purpose of the present invention toprovide a retaining keeper assembly for a hoisting device that will besealed.

It is a further object and purpose of the present invention to provide aretaining keeper assembly for a hoisting device which will maintain afluid tight seal.

While there are many different designs for hoisting devices, somedesigns, such as various pulley blocks and block cases, provide limitedspace in order to access the individual components. Assembly anddisassembly is, thus, made difficult.

Accordingly, it is an object and purpose of the present invention toprovide a retaining keeper assembly for a hoisting device whereincomponents may be easily accessed in limited space conditions.

It is a further object and purpose of the present invention to provide aretaining keeper assembly for a hoisting device that may be retrofittedto existing hoisting devices.

SUMMARY OF THE INVENTION

The present invention is directed to a retaining keeper assembly for ahoisting device, such as a pulley block.

In an initial preferred embodiment, the hoisting device includes a lowerblock case having a cylindrical recessed opening for receipt of a shank.

A shank supporting a load carrying member, such as a hook, terminates inan end having a plurality of parallel circumferential grooves orrecesses in the shank. Each of the grooves is perpendicular to an axisof the shank. The shank passes through the circular cylindrical openingin the lower block case. A thrust bearing fits over and surrounds theshank below the level of the circumferential grooves and is supported inthe cylindrical recess of the lower block case. The thrust bearingaccommodates rotational or swivel movement between the lower block andthe shank.

The retaining keeper assembly includes a split retaining collarfashioned from a pair of semi-circular halves. When the halves arebrought together, they form a cylindrical collar having a plurality ofinterior circular protrusions. The interior circular protrusions matewith the grooves in the shank. The collar rests on the thrust bearing sothat the collar prevents axial movement of the shank. Load force passesfrom the hook to the retaining collar, through the thrust bearing andthen to the case.

In an initial preferred embodiment, a cylindrical retaining collar coverhas cylindrical walls, a closed top and an open bottom. The cylindricalwalls of the retaining collar cover have an inner diameter which closelyfit the outer diameter of the retaining collar when the collar halvesare brought together around the shank. The retaining collar coverentirely surrounds the retaining collar halves and also keeps them fromseparating.

The retaining keeper assembly also includes a fastener mechanism inorder to removably fasten the retaining collar cover to the collar andto the shank. A pair of fasteners passes through openings in theretaining collar cover and engages threaded openings in the retainingcollar halves. A pair of fasteners pass through openings in theretaining collar cover and engages threaded openings in the end of theshank.

A flexible circular seal has an inner diameter which mates with theexterior of the retaining collar cover and an outer diameter which mateswith the cylindrical recess of the lower block case, thereby forming afluid tight seal.

In an alternate preferred embodiment, the split retaining collar mateswith the shank as described in the initial embodiment. A cylindricalretaining collar keeper ring has cylindrical walls, and an open top andan open bottom. The cylindrical walls of the retaining collar keeperring have an inner diameter which closely fit the outer diameter of theretaining collar when the collar halves are brought together around theshank. The keeper ring, thus, keeps the collar halves from separating. Apair of circular retaining rings are positioned adjacent the open topand open bottom of the keeper ring and trap the keeper ring in place.The retaining rings are received in external retaining grooves recessedinto the external surface of the retaining collar. A cover havingcylindrical walls, an open bottom and a closed top may be placed overthe assembled keeper ring, the retaining rings and the split halves ofthe retaining collar.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an initial preferred embodiment of aretaining keeper assembly for a hoisting device constructed inaccordance with the present invention with a portion of the hoistingdevice removed for ease of viewing;

FIG. 2 is an exploded view of a retaining keeper assembly for a hoistingdevice as shown in FIG. 1;

FIG. 3 is a partial sectional view of the retaining keeper assemblyshown in FIG. 1; and

FIG. 4 is an exploded view of an alternate preferred embodiment of aretaining keeper assembly for a hoisting device.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments discussed herein are merely illustrative of specificmanners in which to make and use the invention and are not to beinterpreted as limiting the scope of the instant invention.

While the invention has been described with a certain degree ofparticularity, it is to be noted that many modifications may be made inthe details of the invention's construction and the arrangement of itscomponents without departing from the spirit and scope of thisdisclosure. It is understood that the invention is not limited to theembodiments set forth herein for purposes of exemplification.

Referring to the drawings in detail, FIG. 1 is a perspective view of aninitial preferred embodiment of a retaining keeper assembly 10 shown inuse with a hoisting device. In a preferred embodiment of the presentinvention displayed, a tubing block with a hook 12 used for oilfieldtubing applications is shown. It will be appreciated that other types ofhooks, shackles or lifting devices might be employed within the spiritand scope of the present invention.

The hook 12 is designed to permit rotation or swivel movement between itand a hoisting device. The hoisting device may take many forms, such asa pulley block having sheaves and an upper and lower case. Lower blockcase 14 is shown in FIG. 1 with the balance of the pulley block removedfor ease of viewing.

FIG. 2 illustrates an exploded view of the retaining keeper assembly 10so that the various elements or components are visible.

A shank 16 extends from the hook 12. The shank 16 terminates in an endhaving a plurality of parallel circumferential grooves 18 or recesses inthe shank, each of the grooves being perpendicular to an axis of theshank 16.

The shank 16 passes through a circular opening 20 in the lower blockcase 14. The lower block case includes a cylindrical recess into whichis received a circular thrust bearing 24. When installed, the circularthrust bearing 24 fits over and surrounds the shank 16 below the levelof the grooves 18. The thrust bearing 24 accommodates rotational orswivel movement between the lower block case 14 and the shank 16.

The retaining keeper assembly 10 also includes a split retaining collarfashioned from a pair of semi-circular halves 26 and 28. The retainingcollar halves 26 and 28 are brought together to form a cylindricalcollar having a plurality of interior circular protrusions 30. Theinterior circular protrusions mate with the grooves 18 in the shank 16.A base of the retaining collar rests on and is supported by the thrustbearing. The collar, thus, prevents axial movement of said shaft. Greaseor lubricant may be inserted between the grooves 18 and the protrusionsof the collar, although the collar and shank move together onceassembled.

A cylindrical retaining collar cover 32 has cylindrical walls, a closedtop and an open bottom. The cylindrical retaining collar cover 32 has aninner diameter slightly larger than the outer diameter of the retainingcollar when the collar halves 26 and 28 are brought together around theshank 16. When assembled as shown in FIG. 1, the retaining collar cover32 entirely surrounds the retaining collar halves 26 and 28 and alsokeeps them from separating.

The retaining keeper assembly 10 also includes a fastener mechanism inorder to removably fasten the retaining collar cover 32 to the collarand to the shank 16. A pair of fasteners in the form of threaded bolts34 pass through openings in the retaining collar cover 32 and engagethreaded openings 36 in the retaining collar halves 26 and 28. A pair offasteners in the form of threaded bolts 38 pass through openings in theretaining collar cover 32 and engage threaded openings 42 in the shank16. Rotational movement of the shank, thus, causes rotational movementof the split retaining collar and the retaining collar cover.

A flexible circular seal 40 has an inner edge which mates with theexterior cylindrical walls of the retaining collar cover 32. Thecircular seal also has an outer edge which will mate with thecylindrical recess 22 of the lower block case 14. Accordingly, when thecircular seal 40 is in place, it creates a fluid tight seal between theretaining collar cover and the block case 14.

An optional cap bolt 44 may be inserted in a center opening through thetop of the retaining collar cover 32. Once the other fasteners 34 and 38have been removed and the seal 40 removed, the cap bolt 44 may be usedby rotating in a clockwise direction to force the retaining collar coveraway from the top of the shank. The cap bolt, thus, will assist indisassembly of the retaining keeper assembly.

FIG. 3 illustrates a partial sectional view of the retaining keeperassembly as shown in assembled condition in FIG. 1. A bushing 46 may bejuxtaposed between the shank 16 and the lower block case 14 below thethrust bearing. The thrust bearing 24 resides in the cylindrical recessin the lower case. A circular cavity 48 is connected to a passageway 50terminating in a grease zerk 52 so that grease may be supplied to thethrust bearing 24 as it interfaces between the block case 14 and theshank 16. The split retaining collar rests on and is supported on thethrust bearing. It will be observed that the collar, retaining collarcover and shank are fastened together and move together. The circularseal ring 40 on the outside of the cover creates a fluid tight seal.

In order to install the retaining keeper assembly 10 initially, thethrust bearing 24 is inserted into the cylindrical recess of the lowerblock case 14. Thereafter, the shank 16 of the hook is inserted throughthe cylindrical opening in the lower block case 14 and through thethrust bearing. The circular grooves 18 will then be visible extendingfrom the case 14. The split retaining collar will be installed bybringing the halves together around the shank 16 so that the interiorcircular protrusions of the retaining collar mate with the grooves ofthe shank. Thereafter, the open end of the cylindrical retaining collarcover 32 is slid over top of the split retaining collar and over top ofthe end of the shank 16. The retaining collar cover 32 is secured to theretaining collar with fasteners and the retaining collar cover issecured to the shank with fasteners. A cap bolt or other cover may beinstalled in the top opening to keep it in closed position. Finally, thecircular seal 40 is brought over top of the retaining collar cover andinto the recess of the block case so that a fluid tight seal is createdbetween the exterior of the retaining collar cover and the block case.

The foregoing procedure is performed in reverse in order to disassemblethe retaining keeper assembly 10. The retaining keeper assembly may beeasily assembled and easily disassembled for maintenance and repair.

An alternate preferred embodiment 60 of the retaining keeper assembly isshown in exploded view in FIG. 4. The retaining keeper assembly 60 hasparticular application on open style blocks. A shank 62 extends from ahoisting device (not shown in FIG. 4) as described in detail above withrespect to the embodiment shown in FIGS. 1 through 3. The shank 62terminates in an end having a plurality of parallel, circumferentialgrooves 64 or recesses in the shank, each of the grooves 64 beingperpendicular to an axis of the shank 62. The shank 62 passes through anopening in a trunnion 86 of a block (not shown). A circular thrustbearing 66 fits over and surrounds the shank 62 below the level of thegroove 64. From the foregoing it will be appreciated that the assembly60 rotates on the thrust bearing. The thrust bearing 66 accommodatesrotation or swivel movement between the trunnion 86 of a block and theshank 62.

The retaining keeper assembly 60 includes a split retaining collarfabricated or fashioned from a pair of semi-circular halves 68 and 70.The retaining collar halves 68 and 70 are brought together to form acylindrical collar having a plurality of interior circular protrusions72. The interior circular protrusions 72 are each perpendicular to theaxis of the shank and mate with the grooves 64 in the shank 62. Thesplit retaining collar, thus, prevents axial movement of the shaft 62.Grease or lubricant may be inserted between the grooves 64 in the shankand the protrusions 72 of the collar, although the collar and shank movetogether once assembled. The base of the split retaining collar forms abearing mating surface with the thrust bearing 66 providing a rotatingassembly.

A cylindrical retaining collar keeper ring 74 has cylindrical walls andan open top and an open bottom. The keeper ring 74 has an inner diameterslightly larger than the outer diameter of the retaining collar when thecollar halves 68 and 70 are brought together around the shank 62. Whenassembled, the retaining collar keeper ring 74 surrounds the retainingcollar halves 68 and 70 and keeps them from separating. The keeper ring74 may be fabricated from steel or other rugged material. The axiallength of the keeper ring 74 is less than the axial length of thecollar.

A pair of retaining rings 76 and 78 are positioned adjacent the open topand adjacent the open bottom of the keeper ring 74 and trap the keeperring in place. When installed, the retaining rings 76 and 78 preventaxial movement of the keeper ring 74. The diameter of each retainingring may be expanded slightly so that they can fit over the outsidediameter of the collar. In one configuration, the retaining rings arespring steel leaves but other designs are possible. The retaining rings76 and 78 are received in external retaining grooves 80 and 82 recessedinto the exterior surface of the halves 68 and 70 of the collar.

Finally, a cover 84 having cylindrical walls, an open bottom and aclosed top may be placed over the assembled keeper ring 74, retainingrings 80 and 82, and the split halves 68 and 70. The cover keeps dustand dirt away from the assembly and may be composed of nylon, rubber orother material.

In order to install the retaining keeper assembly 60, the shank 62 ofthe lifting device is inserted through the thrust bearing 66. Thecircumferential grooves 64 of the shank will then be visible andaccessible. The split retaining collar will then be installed bybringing the halves 68 and 70 together around the shank 62 so that theinterior circular protrusions 72 of the retaining collar mate with thecircumferential grooves 64 of the shank 62.

Thereafter, the keeper ring 74 is slid over the top of the splitretaining collar and over the top of the end of the shank 62. The keeperring 74 is held in place and secured to the halves 68 and 70 with theretaining rings 76 and 78.

Thereafter, the cover 84 having cylindrical walls and an open bottom isbrought over top of the assembled keeper ring 74, retaining rings 76 and78, and halves 68 and 70. The interior of the cover 84 may friction fitwith the exterior of the keeper ring 74.

The foregoing procedure is performed in reverse order in order todisassemble the retaining keeper assembly 60. It will be seen from theforegoing that the retaining keeper assembly 60 may be easily assembledand easily disassembled for maintenance, inspection and repair.

Whereas, the present invention has been described in relation to thedrawings attached hereto, it should be understood that other and furthermodifications, apart from those shown or suggested herein, may be madewithin the spirit and scope of this invention.

1. A retaining keeper assembly for a hoisting device, which assemblycomprises: a shank having a plurality of circumferential groovesperpendicular to an axis of said shank; a thrust bearing surroundingsaid shank and supported by said hoisting device; a split retainingcollar having a plurality of interior circular protrusions which matewith said circumferential grooves in said shank; a cylindrical retainingkeeper ring having an open top and an open bottom, said keeper ringhaving an inner diameter slightly larger than an outer diameter of saidretaining collar; and at least one retaining ring surrounding said splitretaining collar to prevent axial movement of said keeper ring.
 2. Aretaining keeper assembly as set forth in claim 1 including acylindrical cover having an open bottom and a closed top receivable oversaid keeper ring.
 3. A retaining keeper assembly as set forth in claim 1including a pair of said retaining rings, one above and one below saidkeeper ring.
 4. A retaining keeper assembly as set forth in claim 3wherein a diameter of each retaining ring is expandable.
 5. A retainingkeeper assembly as set forth in claim 1 wherein said hoisting device isa pulley block.
 6. A retaining keeper assembly as set forth in claim 1wherein said interior circular protrusions and said circumferentialgrooves in said shank are each perpendicular to said shank.
 7. Aretaining keeper assembly as set forth in claim 1 wherein said splitretaining collar is a pair of semi-circular halves.
 8. A retainingkeeper assembly as set forth in claim 1 wherein said shank supports ahook or hooks.
 9. A retaining keeper assembly as set forth in claim 1wherein said shank supports a swivel.
 10. A method of installing aretaining keeper assembly for a hoisting device wherein such methodcomprises: installing a thrust bearing surrounding a shank supported bysaid hoisting device; installing a shank having a plurality ofcircumferential grooves through said thrust bearing wherein saidcircumferential grooves are perpendicular to an axis of said shank;installing a split retaining collar having a plurality of interiorcircular protrusions around said grooves of said shank; sliding acylindrical retaining keeper ring over said split retaining collar andsaid shank; and installing at least one retaining ring around said splitretaining collar adjacent said keeper ring to prevent axial movement ofsaid keeper ring.
 11. A method as set forth in claim 10 wherein saidsplit retaining collar is split into a pair of semi-circular halves. 12.A method as set forth in claim 10 wherein said step of installing saidone keeper ring includes installing a pair of said retaining rings. 13.A method as set forth in claim 10 including the additional step ofinstalling a cover over said retaining rings, said keeper ring and saidsplit collar.
 14. A method as set forth in claim 10 wherein the stepsare performed in reverse order to disassemble the retaining keeperassembly.